A skateboarder on a half-pipe changes his velocity from 6.0 m/s forwards to 4.0 m/s backward in 5.0 s. What is the acceleration of the skateboarder?

Ignoring details associated with friction, extra forces exerted by arm and leg muscles, and other factors, we can consider a pole vault as the conversion of an athlete's running kinetic energy to gravitational potential energy.

When you let go of a rubber band, stored elastic energy is transformed into what kind of energy?

How does density affect refraction? Diamonds are a very dense material. Predict what would happen to the light ray if you projected it from air through a diamond.

A spring has a force constant of 500.0 N/m. Show that the potential energy stored in the spring is as follows: a. 0.400 J when the spring is stretched 4.00 cm from equilibrium b. 0.225 J when the spring is compressed 3.00 cm from equilibrium c.

What is the difference between action and reaction?

An object has a mass of 8.00 kg. What is the gravitational force on the object by the earth?

Which of the following best characterizes the free energy change ΔG for an endothermic reaction under physiological conditions? A. The sign of ΔG is positive B. The sign of ΔG is zero C. The sign of ΔG is negative D.

In a recent hockey game, one player (m=100kg) was moving at a velocity of 8 m/s when he ran into another player (m=300kg) who was at rest (v=0m/s). After the collision, the two players were stuck together (moving with the same velocity).

In a laser, electrical energy is changed to light energy, and a small amount of the energy is wasted as heat. Describe the total amount of the heat in the system (using the conservation of energy).

What is the name for a star and planets held together by gravity? A. solar system B. galaxy C. black hole D. supernova